Is the motor right size for my boat???

[pstldrvn1]

i have a 1980 jay-bee runabout. 21" transom.. motor is 1963 evinrude lark v 40hp.. shaft length is 18". will that work on this boat or do i need a longer shaft motor??.. need to know asap. dont want to buy if it wont fit. thanks all

 

[JB]

Re: Is the motor right size for my boat???

Howdy, pstldrvn.

Welcome to iboats. :welcome:

How did you take those measurements? Neither is standard.

Transoms are measured vertically from the top to a point even with the bottom. Sounds like yours is a 20".

What is the model number of the outboard? That will tell if it is a short (15") or long (20") shaft

 

[matt167]

Re: Is the motor right size for my boat???

18" is considered long shaft so it should work. That old Evinrude is a tough motor, but is 40hp enough for the hull?

 

[matt167]

Re: Is the motor right size for my boat???

Howdy, pstldrvn.

Welcome to iboats. :welcome:

How did you take those measurements? Neither is standard.

Transoms are measured vertically from the top to a point even with the bottom. Sounds like yours is a 20".

What is the model number of the outboard? That will tell if it is a short (15") or long (20") shaft

I have seen several of these old 40hp Big twins. listed at 18" long shaft and 16" short shaft.. Don't know why as I'v never had a chance to measure one. They might actually measure that by the traditional way of taking the measurement but still fit std transom heights.

 

[pstldrvn1]

Re: Is the motor right size for my boat???

thanks matt.. i believe youre right about the 20" transom.. as far as the motor the guy told me it was 18". and that the model # is 40373d

 

[pstldrvn1]

Re: Is the motor right size for my boat???

and i believe he said he measured from inside the top of mount to the cavitation plate

 

[southkogs]

Re: Is the motor right size for my boat???

Even if it fits ... a '63 40HP on a 1980 runabout? I'm gonna' bet that boat is rated at least 70HP. I'm with Matt, you sure that's enough "oomph" for the boat?

Welcome aboard.

 

[pstldrvn1]

Re: Is the motor right size for my boat???

i hope it is! lol... my dad's 20' pontoon has a 40hp and it cruises!! we even pull tubes. and i believe this boat only weighs 750lbs.. its not very big and not much interior... i mainly just want it as a fishing boat on a medium lake that is usually fairly calm

 

[southkogs]

Re: Is the motor right size for my boat???

It may well be enough ... I learned to water ski behind a '58 35HP Evinrude Lark. It was on a 14' runabout and it did okay. But that was max rating for the boat itself.

If the boat in question is rated for 70HP, and you've only got (considerably older) 40HP - you're at about 57% of your max. That means you might be underpowering the hull (general rule of thumb is at least 75% of max).

I would really wanna' try it on the water before I committed to it.

 

[matt167]

Re: Is the motor right size for my boat???

It's not going to run a 700# hull very well. Probably 70-100 HP rated hull... As an example, my Custom Craft weighs 450 lbs ( brochure listing ), it is rated for a 50HP and a 65hp Mercury has been on the back of it since 1964... The 40hp 'might' bring your boat up on plane with 1 person and little gear, but really you will be best running displacement speeds

 

[pstldrvn1]

Re: Is the motor right size for my boat???

i dont know the weight of the hull exactly. couldnt find much info about it. i know its a 1980 and its just over 15' long and the page i found said max HP was 100. n yea it would be nice if i could test it before i commit but i am getting the motor for $75, controls and all, so even if it doesnt work i wont be out alot of money and if it does then i got a steal!

 

[pstldrvn1]

Re: Is the motor right size for my boat???

 

[pstldrvn1]

Re: Is the motor right size for my boat???

that is what the motor would be going on... if anyone has any info about this boat would be helpful too. all i know is its 1980. waiting on the title so i dont know the make or model yet to look anything up

 

[southkogs]

Re: Is the motor right size for my boat???

... you won't like the 40HP on that boat. I'm thinking you want a 70HP.

 

[bonz_d]

Re: Is the motor right size for my boat???

... you won't like the 40HP on that boat. I'm thinking you want a 70HP.

Myself am thinking a 55hp minimum. But run that 40 and look for a bigger engine. Those 50 and 55hp Johnnyrudes were very common and can usually found at a reasonable price.

 

[southkogs]

Re: Is the motor right size for my boat???

Myself am thinking a 55hp minimum. But run that 40 and look for a bigger engine. Those 50 and 55hp Johnnyrudes were very common and can usually found at a reasonable price.

A 50HP Johnson/Evinrude or (if it's rated for it) the 70HP Johnson/Evinrude are fantastic motors. I've had both. The 50 I had just wouldn't die ... heck, the dude I gave it to is probably still running it.

 

[pstldrvn1]

Re: Is the motor right size for my boat???

thanks all.. ill def keep my eyes peeled for a bigger motor.. in the meantime im having fun trying to figure out how to get it all hooked up!! :laugh:

 

[bonz_d]

Re: Is the motor right size for my boat???

A 50HP Johnson/Evinrude or (if it's rated for it) the 70HP Johnson/Evinrude are fantastic motors. I've had both. The 50 I had just wouldn't die ... heck, the dude I gave it to is probably still running it.

Which is why I suggested the 55hp. In my area I can also find many 60 and 70hp 3 cylinders but they are usually also twice the money.

 

[JimS123]

Re: Is the motor right size for my boat???

The motor is a 1970 long shaft Evinrude 40.0 HP. By the SN you gave its not a 1964. So, it will fit the boat fine.

You said 1980 runabout but you didn't say how long, so everybody is jumping to conclusions about it's usefullness. I had one just like it years ago, and it was a strong runner. With the right prop it would do anything for me. Setup is the key - anybody can just throw more HP at it!

Now, after saying that, I would advise against buying it anyway. It's a selectric shift. Very problematic lower unit and hard to get parts. If you could find the "regular" model (not the Lark) with a mechanical shift, I would jump on it in a heartbeat.

 

[pstldrvn1]

Re: Is the motor right size for my boat???

The motor is a 1970 long shaft Evinrude 40.0 HP. By the SN you gave its not a 1964. So, it will fit the boat fine.

You said 1980 runabout but you didn't say how long, so everybody is jumping to conclusions about it's usefullness. I had one just like it years ago, and it was a strong runner. With the right prop it would do anything for me. Setup is the key - anybody can just throw more HP at it!

Now, after saying that, I would advise against buying it anyway. It's a selectric shift. Very problematic lower unit and hard to get parts. If you could find the "regular" model (not the Lark) with a mechanical shift, I would jump on it in a heartbeat.

unfortunately its already bought! lol.. seems like it was taken well care of though, very solid.. im just having trouble figuring the wiring out and making it fit this boat right... btw the boat ive found out is a 1980 jaybee fish n ski 575. 15'3". max hp rating was 100hp.. im sure this motor will push it fine, that is, if i can get it rigged up haha